An antineuronal antibody cross-reacting with erythrocytes and lymphocytes in systemic lupus erythematosus.

An antibody with erythrocyte and lymphocyte activity, present in the sera of patients with systemic lupus erythematosus (SLE), demonstrated additional reactivity with neurons. The neuronal reactivity was greater with cortical neurons than with cerebellar and caudate nucleus neurons, was predominantly IgG, and was immunologically specific. Selected sera from 22 patients with active SLE were tested for the presence of antineuronal antibody. Eleven of 12 sera obtained from patients with neuropsychiatric disease demonstrated definite neuron reactivity, in contrast to only 2 of 10 sera obtained from patients without evidence of neuropsychiatric involvement (P less than 0.005). Five of 21 sera from patients with rheumatoid arthritis, but no sera from 5 other disease control groups, contained antineuronal antibody. Serial studies of 2 SLE patients with transient psychotic episodes demonstrated a close association between antibody titer and the appearance of psychosis in one. These observations suggest that the detection of antineuronal antibodies in patients with SLE may be of value in the diagnosis and management of neuropsychiatric complications.